D. Brent Chapman is a consultant in the San Francisco Bay Area, specializing in Internet firewalls. He has designed and built Internet firewall systems for a wide range of clients, using a variety of techniques and technologies. He is also the manager of the Firewalls Internet mailing list. Before founding Great Circle Associates, he was operations manager for a financial services company, a world-renowned corporate research lab, a software engineering company, and a hardware engineering company. He holds a Bachelor of Science degree in electrical engineering and computer science from the University of California, Berkeley. In his spare time, Brent is a volunteer search and rescue pilot, disaster relief pilot, and mission coordinator for the California Wing of the Civil Air Patrol (the civilian auxiliary of the United States Air Force). Elizabeth Zwicky is a senior system administrator at Silicon Graphics and the president of SAGE (the System Administrators Guild). She has been doing large-scale UNIX system administration for 10 years and was a founding board member of both SAGE and BayLISA (the San Francisco Bay Area system administrators' group), as well as a non-voting member of the first board of the Australian system administration group, SAGE-AU. She has been involuntarily involved in Internet security since before the Internet worm. In her lighter moments, she is one of the few people who makes significant use of the "rand" function in PostScript, producing PostScript documents that are different every time they're printed.